Integerating Orb with extensions for laziness/memoization

src/main/scala/leon/invariant/engine/InferenceContext.scala

src/main/scala/leon/invariant/engine/InferenceEngine.scala

...ala/leon/invariant/templateSolvers/NLTemplateSolver.scala

src/main/scala/leon/invariant/util/TreeUtil.scala

testcases/lazy-datastructures/RealTimeQueue.scala

testcases/lazy-datastructures/withOrb/BottomUpMegeSort.scala

testcases/lazy-datastructures/withOrb/Concat.scala

testcases/lazy-datastructures/withOrb/Deque.scala

testcases/lazy-datastructures/withOrb/Esop15Benchmarks.scala

...cases/lazy-datastructures/withOrb/FibonacciMemoized.scala

testcases/lazy-datastructures/withOrb/HammingMemoized.scala

testcases/lazy-datastructures/withOrb/Knapsack.scala

testcases/lazy-datastructures/withOrb/RealTimeQueue.scala

...ases/lazy-datastructures/withOrb/SortingnConcat-orb.scala